BORAX PENTAHYDRATE

BORAX PENTAHYDRATE

CAS No. : 12179-04-3

Synonyms:
Borax pentahydrate; Tincalconite; Borax 5-hydrate; 12179-04-3; Etibor-48; Sodium Tetraborate Pentahydrate; B4H10Na2O12; Sodium tetraborate decahydrate; Borax octahydrate; borone; boron; Borax; Sodium tetraborate,Trace metals grade 99.95%; komex; DISODIUM BICYCLO[3.3.1]TETRABOROXANE-3,7-BIS(OLATE); Disodium 3,7-dioxido-2,4,6,8,9-pentaoxa-1,3,5,7-tetraborabicyclo[3.3.1]nonane decahydrate; Sodium tetraborate decahydrate; Sodium borate phosphate; Phosphoric acid, reaction products with borax, sodium salts; Borax Anhydrous; Borax glass; Borax, fused; Boric acid (H2B4O7), sodium salt; Boron sodium oxide (B4Na2O7); Na2B4O7; Sodium Tetraborate; Sodium Tetraborate, Anhydrous; Sodiumtetraborate; Boron; Boron, metallic; Boron and compounds; boro; Boron-elemental; Boron, elemental; Boron, Amorphous; Boron standard solution, for AAS, 1 mg-ml B in water; boracium; bore; boron atom; Boron Nanorods; Boron powder; Boron Chelate; Boron Nanoprisms; Boron Proteinate; BORaN; 5B; Boron Citrate Blend; Boron Picolinate Blend; Boron nitride nanoplates; Boron Krebs 5% 40M; BORAX PENTAHYDRATE; Boron Glycinate 5% 40M; EC 231-151-2; Boron Trituration 1% 40M; Boron Nanoparticle Dispersion; KSC378S2P; boron citrate/aspartate/glycinate; DTXSID3023922; Hexagonal Boron Nitride crystals; Boron Nanoparticles / Nanopowder; Boron Nitride Nanotubes (BNNT); Hexagonal Nitride Boron Nanoplates; Multilayer h-BN (Boron Nitride) film; Borax pentahydrate; Tincalconite; Borax 5-hydrate; Boron Citrate/Aspartate 5% 40M Bld; Boron, amorphous, powder, (submicron); Single Layer Hexagonal Boron Nitride Film; Boron, >=95% (boron), amorphous powder; Boron, monofilament, 50m, diameter 0.2mm; Boron, crystalline, 90-95%, -325 mesh; Boron, monofilament, 100m, diameter 0.1mm; METHYL-(2Z)3-IODO-2N-ACETYLCROTANOATE; Boron pieces, crystalline, 20mm (0.8in) & down; Boron, purum p.a., >=99.0%, pieces, crystalline; Etibor-48; Boron pieces, crystalline, 10-30mm (0.39-1.2in); Boron, crystalline, 1 cm, 99.7% trace metals basis; Boron, monofilament, 0.080 mm diameter, length 5 m; Q15634214; Boron, crystalline, -60 mesh, 99% trace metals basis; Boron, monofilament, 0.080 mm diameter, length 10 m; Boron, monofilament, length 200 m, 0.080 mm diameter; Boron, Oil based standard solution, Specpure, B 1000g/g; Boron, Oil based standard solution, Specpure, B 5000g/g; Boron 11, 11B, plasma standard solution, Specpure, 11B 100g/ml; Boron, granule, 15 mm nominal granule size, weight 100 g, purity 99%; 14798-13-1; Bor; Boron, microfoil, disks, 10mm, thinness 0.1mum, specific density 23.5mug/cm2, permanent mylar 3.5mum support, 99.6%

Borax Pentahydrate

Etibor-48 (Borax Pentahydrate) (Na2B4O7.5H2O) is a form of sodium borate containing 5 mol H2O molecules which are widely used in the industry. It is obtained in powder or crystal form from Tincal (Na2B4O7.10H2O) ore extracted by the Kırka Boron Works. Production process includes dissolving, settlement with various flocculants (anionic, etc.), centrifugation, filtration, crystallization and drying stages.

Usage and Benefits:
Glass: Borax pentahydrate is added to glass products used for heat insulation as it increases viscosity, surface hardness and durability when added to molten glass intermediates. The most important use of borax pentahydrate is glass fiber in the insulation sector. 
Agriculture: Boron is an element that must be present in soil for the growth and development of plants. Borax pentahydrate is used to increase
agricultural productivity and to obtain higher quality products. It is used as the boron source in fertilizers containing boron.
Ceramics: Borax pentahydrate, which has a high water solubility, is used as the glazing raw material in ceramics.
Fire retardants: Borates are used as fire retardants in various materials. They cover the material by melting and prevent the material from catching fire by severing the contact between the oxygen and the flame.
Metallurgy: Borax pentahydrate is used as a protective slag-former and fusing accelerator in the non-ferrous metal industry due to the property of forming a smooth, adhesive, protective, clean and burr-free liquid at high temperatures.
Construction: Borax pentahydrate is used as a plastering material in the construction industry for the purpose of heat and sound insulation.
Anti-freeze: Borax pentahydrate is used as an additive to the antifreeze mixture in the cooling systems of vehicles.
Adhesive: Borax pentahydrate is used in the regulation of the viscosities of starchy adhesives and the solvents of casein-based adhesives.

Borax pentahydrate, also known as sodium borate, sodium tetraborate, or disodium tetraborate, is a compound with formula Na2H4B4O9•nH2O or, more precisely, [Na•(H2O)+m]2 [B4O5(OH)2−4].
The formula is often improperly written as Na2B4O7•(n+2)H2O, reflecting an older incorrect understanding of the anion's molecular structure. The name may refer to any of a number of closely related boron-containing mineral or chemical compounds that differ in their water of crystallization content. The most commonly encountered one is the octahydrate Na2H4B4O9•8H2O or [Na(H2O)+4]2 [B4O5(OH)2−4] (or Na2B4O7•10H2O, the "decahydrate", in the older notation).[9] It is a colorless crystalline solid that dissolves in water.

Borax pentahydrate is a component of many detergents, cosmetics, and enamel glazes. It is used to make buffer solutions in biochemistry, as a fire retardant, as an anti-fungal compound, in the manufacture of fiberglass, as a flux in metallurgy, neutron-capture shields for radioactive sources, a texturing agent in cooking, as a cross-linking agent in slime, as an alkali in photographic developers, as a precursor for other boron compounds, and is useful as an insecticide (similarly to boric acid).

In artisanal gold mining, Borax pentahydrate is sometimes used as part of a process (as a flux) meant to eliminate the need for toxic mercury in the gold extraction process, although it cannot directly replace mercury. Borax pentahydrate was reportedly used by gold miners in parts of the Philippines in the 1900s.

Borax pentahydrate was first discovered in dry lake beds in Tibet and was imported via the Silk Road to the Arabian Peninsula in the 8th century AD. Borax pentahydrate first came into common use in the late 19th century when Francis Marion Smith's Pacific Coast Borax pentahydrate Company began to market and popularize a large variety of applications under the 20 Mule Team Borax pentahydrate trademark, named for the method by which Borax pentahydrate was originally hauled out of the California and Nevada deserts.

Structure
The term Borax pentahydrate is often used for a number of closely related minerals or chemical compounds that differ in their crystal water content:
anhydrous sodium tetraborate, Na2B4O7
sodium tetraborate pentahydrate, Na2B4O7·5H2O
sodium tetraborate decahydrate, Na2B4O7·10H2O or equivalently the octahydrate, Na2B4O5(OH)4·8H2O
From the chemical perspective, Borax pentahydrate contains the [B4O5(OH)4]2− ion. In this structure, there are two four-coordinate boron centers and two three-coordinate boron centers.

Reactions
Borax pentahydrate is also easily converted to boric acid and other borates, which have many applications. Its reaction with hydrochloric acid to form boric acid is:
Na2B4O7·10H2O + 2 HCl → 4 B(OH)3 + 2 NaCl + 5H2O
The "decahydrate" is sufficiently stable to find use as a primary standard for acid base titrimetry.
When Borax pentahydrate is added to a flame, it produces a yellow green color.[16] Borax pentahydrate is not used for this purpose in fireworks due to the overwhelming yellow color of sodium. Boric acid is used to color methanol flames a transparent green.
Borax pentahydrate is very soluble in ethylene glycol, moderately soluble in diethylene glycol and methanol, slightly soluble in acetone.[17] It is poorly soluble in cold water, but its solubility increases significantly with temperature.

Etymology
The English word Borax pentahydrate is Latinized: the Middle English form was boras, from Old French boras, bourras. That may have been from medieval Latin baurach (another English spelling), borac(-/um/em), Borax pentahydrate, along with Spanish borrax (> borraj) and Italian borrace, in the 9th century. Another name for Borax pentahydrate is tincal, from Sanskrit.[12]
The word tincal /ˈtɪŋkəl/ "tinkle", or tincar /ˈtɪŋkər/ "tinker", refers to crude Borax pentahydrate, before it is purified, as mined from lake deposits in Tibet, Persia, and other parts of Asia. The word was adopted in the 17th century from Malay tingkal and from Urdu/Persian/Arabic تنکار‎ tinkār/tankār; thus the two forms in English. These all appear to be related to the Sanskrit टांकण ṭānkaṇa.[19][20]

Natural sources
Borax pentahydrate "cottonball"
Borax pentahydrate occurs naturally in evaporite deposits produced by the repeated evaporation of seasonal lakes. Fibrous nodules of ulexite and proberite (sodium and calcium borate minerals) known as "cottonball" were found in salt deposits on the valley floor of California's Death Valley in the 1880s and taken to market on 20-mule team wagons. By the 1890s railroads were transporting purer forms of mined Borax pentahydrate such as colemanite, kernite, priceite, and ulexite.
The most commercially important deposits are found in: Turkey; Boron, California; and Searles Lake, California. Borax pentahydrate has been found at many other locations in the Southwestern United States, the Atacama desert in Chile, and in Bolivia, Tibet, and Romania.
Naturally occurring Borax pentahydrate is refined by a process of recrystallization.[22]
Borax pentahydrate can be produced synthetically from other boron compounds.

Uses
Borax pentahydrate-based laundry detergent
Household products
Borax pentahydrate is used in various household laundry and cleaning products,[23] including the "20 Mule Team Borax pentahydrate" laundry booster, "Borax pentahydrateo" powdered hand soap, and some tooth bleaching formulas.[24]

pH buffer
Borate ions (commonly supplied as boric acid) are used in biochemical and chemical laboratories to make buffers, e.g. for polyacrylamide gel electrophoresis of DNA and RNA, such as TBE buffer (borate buffered tris-hydroxymethylaminomethonium)[25][26] or the newer SB buffer or BBS buffer (borate buffered saline) in coating procedures. Borate buffers (usually at pH 8) are also used as preferential equilibration solution in dimethyl pimelimidate (DMP) based crosslinking reactions.

Co-complexing agent
Borax pentahydrate as a source of borate has been used to take advantage of the co-complexing ability of borate with other agents in water to form complex ions with various substances. Borate and a suitable polymer bed are used to chromatograph non-glycosylated hemoglobin differentially from glycosylated hemoglobin (chiefly HbA1c), which is an indicator of long-term hyperglycemia in diabetes mellitus.

Water-softening agent
Borax pentahydrate alone does not have a high affinity for the hardness cations, although it has been used for water-softening. Its chemical equation for water-softening is given below:
Ca2+ (aq) + Na2B4O7 (aq) → Ca B4O7 (s)↓ + 2 Na+ (aq)
Mg2+ (aq) + Na2B4O7 (aq) → Mg B4O7 (s)↓ + 2 Na+ (aq)
The sodium ions introduced do not make water ‘hard’. This method is suitable for removing both temporary and permanent types of hardness.

Flux
A mixture of Borax pentahydrate and ammonium chloride is used as a flux when welding iron and steel. It lowers the melting point of the unwanted iron oxide (scale), allowing it to run off. Borax pentahydrate is also used mixed with water as a flux when soldering jewelry metals such as gold or silver, where it allows the molten solder to wet the metal and flow evenly into the joint. Borax pentahydrate is also a good flux for "pre-tinning" tungsten with zinc — making the tungsten soft-solderable.[27] Borax pentahydrate is often used as a flux for forge welding.

Small-scale gold mining
Traction engine hauling Borax pentahydrate, Death Valley, 1904
Borax pentahydrate is replacing mercury as the preferred method for extracting gold in small-scale mining facilities. The method is called the Borax pentahydrate method and is used in the Philippines.

Flubber
Main article: Flubber (material)
A rubbery polymer sometimes called Slime, Flubber, 'gluep' or 'glurch' (or erroneously called Silly Putty, which is based on silicone polymers), can be made by cross-linking polyvinyl alcohol with Borax pentahydrate. Making flubber from polyvinyl acetate-based glues, such as Elmer's Glue, and Borax pentahydrate is a common elementary-science demonstration.

Food additive
Borax pentahydrate, given the E number E285, is used as a food additive, but is banned in some countries, including the United States, China,[31] and Thailand. As a consequence, certain foods, such as caviar, produced for sale in the United States contain higher levels of salt to assist preservation.[32] In addition to its use as a preservative, Borax pentahydrate imparts a firm, rubbery texture to food. In China, Borax pentahydrate (Chinese: 硼砂; pinyin: péng shā or Chinese: 月石; pinyin: yuè shí) has been found in foods including wheat and rice noodles named; lamian, shahe fen, kway teow, and chee cheong fun.[33] In Indonesia, it is a common, but forbidden, additive to such foods as noodles, bakso (meatballs), and steamed rice. The country's Directorate of Consumer Protection warns of the risk of liver cancer with high consumption over a period of five to ten years.[34] Borax pentahydrate was one of the chemicals used in 19th century industrialised food production that was investigated by Dr. Harvey W. Wiley with his famous 'Poison Squad' as part of the US Department of Agriculture. This lead up to the 1906 Pure Food and Drug Act. A landmark event in the early history of food regulation in the United States.

Other uses
Rio Tinto Borax pentahydrate mine pit, Boron, California
Medicinal
Anti-fungal foot soak
Treatment for thrush in horses' hoofs
Is found in some commercial vitamin supplements
Other
Ingredient in enamel glazes[35]
Component of glass, pottery, and ceramics[36]
Used as an additive in ceramic slips and glazes to improve fit on wet, greenware, and bisque[citation needed]
Fire retardant[37]
Anti-fungal compound for cellulose insulation[36]
Moth proofing 10% solution for wool[38]
Pulverized for the prevention of stubborn pests (e.g. German cockroaches) in closets, pipe and cable inlets, wall panelling gaps, and inaccessible locations where ordinary pesticides are undesirable[39]
Precursor for sodium perborate monohydrate that is used in detergents, as well as for boric acid and other borates[citation needed]
Tackifier ingredient in casein, starch and dextrin based adhesives[40]
Precursor for boric acid, a tackifier ingredient in polyvinyl acetate, polyvinyl alcohol based adhesives
To make indelible ink for dip pens by dissolving shellac into heated Borax pentahydrate[41]
Curing agent for snake skins[citation needed]
Curing agent for salmon eggs, for use in sport fishing for salmon[citation needed]
Swimming pool buffering agent to control pH[42]
Neutron absorber, used in nuclear reactors and spent fuel pools to control reactivity and to shut down a nuclear chain reaction[43]
As a micronutrient fertilizer to correct boron-deficient soils.[44][45]
Preservative in taxidermy[46]
To color fires with a green tint[47]
Was traditionally used to coat dry-cured meats such as hams to improve the appearance and discourage flies.[48][49][34]
For stopping car radiator and engine block leaks[citation needed]
Used by blacksmiths in forge welding[50]
Used as a woodworm treatment (diluted in water)[citation needed]
Used as an insecticide in some ant baits. It kills ants slowly, allowing the ants time to bring the poison back to the colony, killing the queen and eventually the entire colony.
Deodorizer for carpets, sprinkle on and leave for a while and vacuum it up

Toxicity
Borax pentahydrate, sodium tetraborate decahydrate, according to one study, is not acutely toxic. Its LD50 (median lethal dose) score is tested at 4.55-6.08 g/kg in rats as determined by US EPA (1969),[51] later in 1972 found to be 4.5 g/kg,[52] meaning that a significant dose of the chemical is needed to cause severe symptoms or death. The lethal dose is not necessarily the same for humans. On pesticide information websites it is listed as a non-lethal compound and of no hazardous concerns.
Borax pentahydrate has been in use as an insecticide in the United States with various restrictions since 1946. All restrictions were removed in February 1986 due to the low toxicity of Borax pentahydrate, as reported in two EPA documents relating to boric acid and Borax pentahydrate.

EPA has determined that, because they are of low toxicity and occur naturally, boric acid and its sodium salts should be exempted from the requirement of a tolerance (maximum residue limit) for all raw agricultural commodities.[53]
Although it cited inconclusive data, a re-evaluation in 2006 by the EPA still found that "There were no signs of toxicity observed during the study and no evidence of cytotoxicity to the target organ."[55] In the reevaluation, a study of toxicity due to overexposure was checked and the findings were that "The residential handler inhalation risks due to boric acid and its sodium salts as active ingredients are not a risk concern and do not exceed the level of concern..." but that there could be some risk of irritation to children inhaling it if used as a powder for cleaning rugs
Sodium tetraborate decahydrate has no known hazard issues.

Overexposure to Borax pentahydrate dust can cause respiratory irritation, while no skin irritation is known to exist due to external Borax pentahydrate exposure. Ingestion may cause gastrointestinal distress including nausea, persistent vomiting, abdominal pain, and diarrhea. Effects on the vascular system and human brain include headaches and lethargy, but are less frequent. In severe cases, a "beefy" red rash affecting the palms, soles, buttocks and scrotum has occurred. 
Due to concerns about the toxicity of Borax pentahydrate which was withdrawn as a cleaning and laundry product, sodium sesquicarbonate is sold in the European Union (EU) as "Borax pentahydrate substitute". It is also known as one of the E number food additives E500.
During the 1951 Indianapolis 500, race winner Lee Wallard coated his racing suit with a fire retardant mixture of Borax pentahydrate crystals and water. He suffered serious chafing, and required treatment at the infield hospital after the victory lane celebration.

Risk to fertility and pregnancy
Borax pentahydrate was added to the Substance of Very High Concern (SVHC) candidate list on December 16, 2010. The SVHC candidate list is part of the EU Regulations on the Registration, Evaluation, Authorisation and Restriction of Chemicals 2006 (REACH), and the addition was based on the revised classification of Borax pentahydrate as toxic for reproduction category 1B under the CLP Regulations. Substances and mixtures imported into the EU which contain Borax pentahydrate are now required to be labelled with the warnings "May damage fertility" and "May damage the unborn child".[58] It was proposed for addition to REACH Annex XIV by the ECHA on July 1, 2015.[59] If this recommendation is approved, all imports and uses of Borax pentahydrate in the EU will have to be authorized by the ECHA.[needs update]

Review of the boron toxicity (as boric acid and borates) published 2012 in Journal of Toxicology and Environmental Health concluded: "It clearly appears that human B [boron] exposures, even in the highest exposed cohorts, are too low to reach the blood (and target tissue) concentrations that would be required to exert adverse effects on reproductive functions."

A draft risk assessment released by Health Canada in July 2016 has found that overexposure to boric acid has the potential to cause developmental and reproductive health effects. Since people are already exposed to boric acid naturally through their diets and water, Health Canada advised that exposure from other sources should be reduced as much as possible, especially for children and pregnant women. The concern is not with any one product, but rather multiple exposures from a variety of sources. With this in mind, the department also announced that registrations for certain pesticides that contain boric acid, which are commonly used in homes, will have their registrations cancelled and be phased out of the marketplace. As well, new, more protective label directions are being introduced for other boric acid pesticides that continue to be registered in Canada (for example, enclosed bait stations and spot treatments using gel formulations).

Borax pentahydrate has been used as a laundry additive since about 1900. It can contribute to the softening of hard water by tying up calcium ions, as well as acting as a buffer agent. A traditional use as a sweetening agent for diaper pails is thought to involve the borate inhibition of the urease enzyme, (preventing ammonia formation). The same effect has been patented for deodorizing animal litter. Products based on Borax pentahydrate and formulated with additives can give bleach-like activity when added to the wash.

Disodium tetraborate (Borax pentahydrate) containing 5 or 10 molecules of water is produced mainly from sodium-containing borate ores. The mined ore is crushed and ground before dissolution in a hot recycled aqueous solution containing some Borax pentahydrate. Insoluble gangue (clay particles) present in the hot slurry is separated off to produce a clear concentrated Borax pentahydrate solution. Evaporative cooling of this solution to selected temperatures results in crystallization of the desired products, which are then separated from the residual liquor and dried.

Boron has well-defined biological effects and may be of therapeutic benefit. In the current paper, the effect of boron in the form of Borax pentahydrate was tested in experimental animal model of fulminant hepatic failure (FHF). The syndrome was induced in female Wistar rats by three consecutive daily intraperitoneal injections of thioacetamide (400 mg/kg). In the treatment groups, rats received Borax pentahydrate (4.0 mg/kg) orally for three consecutive days followed by thioacetamide. The group administered with thioacetamide plus vehicle, and the Borax pentahydrate alone treated rats served as controls. In all groups, rats were terminated 4 hr after administering the last dose of thioacetamide, and the tissue/serum was used to measure hepatic levels of thiobarbituric acid reactive substances, reduced glutathione, and various enzymes associated with oxidative stress including peroxide metabolizing enzymes and xanthine oxidase. In thioacetamide treated group, many fold increase in the activity level of serum marker enzymes suggesting FHF was observed that could be brought down significantly in rats receiving boron. Modulation and a correlation in the activity level of oxidant generating enzyme and lipid peroxidation as well as hepatic glutathione level was also observed in rats receiving thioacetamide. In the group receiving boron followed by thioacetamide, these changes could be minimized moderately. The activity level of the peroxide metabolizing enzymes and the tripeptide glutathione, which decreased following thioacetamide treatment were moderately elevated in the group receiving boron followed by thioacetamide. The data clearly shows that Borax pentahydrate partly normalizes the liver and offsets the deleterious effects observed in FHF by modulating the oxidative stress parameters.The dermal irritation potential of Borax pentahydrate and boric acid was studied. Ten mL of 5% aqueous boric acid (17.5 g B/L) were applied under occlusion to the clipped, intact and abraded skin of rabbits and guinea pigs. Sites were scored for irritation at 24 and 72 hours. Both Borax pentahydrate and boric acid were found to be mild to moderate irritants.

Borax pentahydrate production and use in soldering metals, manufacture of glazes and enamels, tanning, curing and preserving skins, buffers, as a complexing or masking agent in analytical chemistry, fireproofing fabrics and as a pharmaceutic aid (alkalizer) may result in its release to the enviornment through various waste streams. Its use as in cleaning compounds, artificially aging wood, as a preservative, either alone or with other antiseptics against wood fungus, fireproofing wood, in cockroach control, use in ant poisons, and for fly control around refuse and manure piles as a larvicide will result in its direct release to the environment. Boron is naturally occurring and ubiquitous in the environment. The most common boron containing ores are alkali and alkaline earth borates, including Borax pentahydrate (Na4B4O2.10H2O), kernite (Na2B4O7.4H2O), colemanite (Ca2B6O11.5H2O), and ulexite (NaCaB5O9.8H2O), and as borosilicate minerals. Boron containing minerals are concentrated in arid regions, such as Turkey and California's Death Valley. Borax pentahydrate is stable to photolysis. Disappearance from soil is by washing out. Persistence in soil is about 2 years, depending on rainfall and soil structure. Borax pentahydrate does not biodegrade. Borax pentahydrate is stable to hydrolysis. Monitoring and use data indicate that the general population may be exposed to Borax pentahydrate via dermal contact with this compound via consumer products containing Borax pentahydrate.